Automatic telephone system.



H. E. HERSHEY 6a G. A. YAOCHOWSKI.

AUTOMATIC TELEPHONE SYSTEM.

APPLccArloN man Nov.2s.1913. 1,209,293. Patented De.19,1916.

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H. E. HERSHEY l (A A. YANUCHUWSKI.

AUTGMATIC TELEPHONE SYSTEM. APPLICATION min Nov. 2s. |913.

Patented "Deer 19, i916 UNITED STATES PATENT OFFICE.

HARRY E. HERSHEY, OF VHITEWATER, KANSAS. AND GEORGE A. YANOCHOWSKI, OF

CHICAGO, ILLINOIS, ASSIGNORS TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS. A CORPORATION OF ILLINOIS.

Application tiled November 28, 1913v lie it known that we. linnn' I. lInnsHnY and (Il-:onor: A\. Yaxotnou'sui, both eitizens ot' the llnited States ota .\n1erira. and residents of 'hitewater` Butler eounty, Kansas. and Chit-ago, '(oolt eounty, Illinois, respeetirely` hare invented eertain new and useful lmproyenu-nts in Automatic Telephone Systems. ol' whieh the following is a speeilieation.

Um' invention relates to improvements in automatie telephone systems. and partielllarly to means t'or releasing the switches of such a system.

Among the novel Features olf our invention is the prorision of a repeater through whit-h any release whit-ll is initiated beyond this repeaterwthat is, on the eonneetor side-ean he transmitted haelt to the apparatus on the subserihens side otd the repeater'.

A t'urther novel l'eature is the means for opening the line eireuit, beyond the repeater when the eonneetor strikes a busy line, whereby the switehes are released over the talking ein-uit instead oil over a trunk-rw lease eonduetor` as is usually the ease.

These and other noyel features and objects of our invention will he more readily understood by ret'erenee to the aeeompanying drawings, in whieh embodiment otA our invention.

Figures 1 and representa eomplete con neetion between a ealling substation A and a ealled substation in a telephone system embodying the prineiples ol our inrention.

The system herein deserihed is of a wellltnown automatie type. linou n as a two-wire system. and is equipped with indiridual or line swilehes t dirided into groups.` eaeh group eontrolled hy a master switeh` such as the master switeh l). and also with group seleetors IC. repeaters li and `eonneetors l, hut it will he readily understood hy those versed in the art thatI additional so-ealled seleetors may he inserted in the tem, thereby inet-easing the eapaeity ot' the eX- ehange without departing from the prineiples ol' our invention. The Vseleetor switehes may he o'l1 a type similar to the selector switeh shown at ll. 'l`he subserihews station is eonneeted with the ventral olliee through the eoniluftois L and Il. whieh terminate in a line switeh (L said switeh being in a group Specification of Letters Patent.

we hare illustrated air` A Patented Dec. 19, 1916. Serial No. 803,525.

governed by a master switch I). By means of the line switch (l the line is extended to the. selector E, whirh in turn extends the connection to the repeater F. The repeater F repeats the impulses to the connector I, whieh latter completes the connection to the ealled subseriher`s telephone A.

The substation A shown herein may be of any suitable or approved. type and coinprises the usual receiver 4, trai'ismitter 5, ringer l and eondenser 7. Being an automatie substation it is also provided with an impulse transmitter or calling device which is represented herein hy a pair of impulse springs Si and t) and an impulse wheel 10, whit-h latter is eontrolled through the medium ot' a linger holedial (not shown) in sueh a manner that the impulse springs S and Sl may he momentarily separated a numher oll times eorresponding to eaeh digit of the number to he called. y

The line switeh (l. whieh is associated with theI line ot the substation is ol' the general type ol line switeh shown in British patent to l. W. James No. 26,301 ot' 1h06, and shown more partieularly in British patent to T. (i. hlal'tin No. 111i) of 101.0, tho eireuits being slightly modified to operate in a system embodying the prineiples of our invention. This line switeh eoml'n'ises, among other details` a plunger (not` shown) attaehed to the end ot' a So-ealled plunger arm Il whieh is eontrolled by the magnet 12. The magnet. 12 eomprises two wimlings. namely. the pull-in winding lil and they holding or eut-oli' winding 1|. The winding 13 operates both the, plunger arm 1l andthe rotanti' armature 15, while the winding 11 is strong enough to operate only the armature l5 and to hold the plunger arln 11 in an operated position after it has heen one@ operated by the pull-in winding 123. The cir euit ot' the pull-in winding 13 is Controlled by the line relay 11S and the relay 17, both ot whieh we preferably 'make Slow acting, i. e., they are Slow to deiinergize a t'ter their energizing eireuits ha re been broken. lVllen the plunger arm 11 is operated, the plunger is forced into a bank of eontaet` springs` foroing the springs 18. 19. QU and :1 into engagement with the lsprings :22. 2S. 24 and Q5. respeetirely. Although only one Set, ot' springs {18V-25) is shown, eaeh line switeh is pro vided with a plurality of such sets, each set forming the terminal of a trunk line leading to a selector` -switch E. Each trunk line is connected in multiple to the corresponding springs of all the switches of the group which is controlled by the master switch D. The switch C is controlled through the mcdium of the line relay 1G, as will be hereinafter more fully. explained.

The master switch D is of the same general type as that disclosed in British patent to R. W. James No. 26,301 of 1906, above referred to, being of the particular type, nowever, disclosed in the above-mentioned British Patent No. 1412) of 1910. The function 0f the master switch, as is well known, is to maintain the plungers of all the idle line switches in position to engage the terminals of an idle trunk line.

The selector E is of the general type of selector switches disclosed in United States Letters Patent No, 815,321, granted March 13, 1906, to Keith, Erickson' and Erickson, the circuits being modified, however, as

shown in British Patent No. 1410 ot 1010,

above referred to, 1n order to operate in a two-Wire system. It comprises, among other details, the line relay 26, vertical and rotary magnets 27 and 2S 'lor operating the switch shaft and shaft wipers 29, 30 and 31, private magnet 32, the release relay 33, the side switch wipers 34 and 35 and the release magnet 30. The private magnet 32 is controlled by the rotary magnet 28 electrically through the medium of the contact point 01, instead ot' mechanically as shown in the selector patent abovevreferred to. The switch shaft (not shown), which has a vertical and a rotary movement, and the line and private wipers 29, 30 and 31 are the direct means of connection between this switch and the repeater F.

The repeater F has a line relay 37, a slow relay 38 and a battery-reversing relay 39. The line relay 37 is normally bridged across the trunk extending to the repeater from' the selector E and is arranged so that when its armature operates in accordance with thc impulses from the subscribcrs station A, it Opens and closes the bridge across the trunk extending to the connector l a corresponding number of times. The function ot this repeater switch is to receive the impulses lrans lnitted from the subscribcrs station and repeut them to the switches farther on. Furthermore, it supplies battery current to the calling line and maintains a holding circuit for the line switch (l and selector E without requiring a third conductor to be included in the trunk line extending to the switches beyond, and in this way the necessity for having a third conductor between oHlccs is eliminated.

The connector switch I is of the same genn eral type of connector switch disclosed in United States Letters Patent No. 815,170.

granted March 13, 1906, to Keith, Erickson and Erickson, the circuits, however, being moditied to adapt the switch to operate in a system in which the central otlice apparatus is controlled by impulses deliv'ered over the two sides ot the line in series. The circuits are otherwise slightly modified to operate in a -system embmlying the principles ol our invention. The connector' is provided with a shaft (not shown) carrying the wipers (il, (i5 and it. The usual side switch comprising thc wipers 39, T0, T1 and T2 is controlled by the private magnet T3 in the usual wellknown nuxnncr. The magnet 'il is the usual release magnet. '.lhtl operations df the switch are controlled through the medium of the double-wound line relay 75. The called subscriber receives talking current through the sowalled back-bridge relay 7G. rl`bc ringing relay T7 is the means through which ringing current is applied to the called lille. For the purpose of supplying battery current Jfor op erating the apparatus and for talking purposes, there are shown batteries li and ll', one terminal olA each being grounded.

Busy signaling current l'or the calling line is provided by the busy signaling machine Q tliig. l). which 'is shown associated with thc line switch l. This busy signaling machine ycomprises` un induction coil or transformer, the primary winding o'l' which is included in a local circuit wiili a lulttcry and an interrupter. Through the medium ot' this interruptor un interrupted` current is supplied to the primary winding, which iuduces an alternating current in the secondary winding, whereby, when said winding is connected with the suliscribefs line a bu?.- zing sound is heard in thc receiver.

A general description ot' the apparatus having been given. it will now be explained how a` connection is established between the substation A and a called substation A. lt will also he explained how. it thc called substation is busy, all o the almaratus is automatically released and returned to normal position` whereby the trunks are kept trom being made busy. while the calling subscriber is given the busy signal through the medium of his individual line switch lt will be assumed that thc number ot thc called substation is i522. llpon the removal olI thc rccciver from the switch-hook at thc substation A preparatm'y to making :i call, an energizing circuit/is closed through the line relav 1t', of the linc switch t. This circuit extends from ground (i through the springs l1 and 4:2, conductor 3, through the substation A, coiuluctor 3, springs` 4l and i3 and the line relay lf3 tobattcry l. The line relay 10, upon energizing, operates to close the circuit of the pull-in winding lil. This circuit extends 'from ground (i2 through the springs if and lo, springs. 4T and 48. pull-in winding 13 und the springs 49 and 50 to battery ll. rlhe pull-in winding 13 operates to cause the armature 15 to torce the springs 41 and 42$ out of engagement with the springs 42 and 44, rcspettively` and also operates to' force the plunger on the plunger arm 11 into the bank ot' contacts 18 to 25, inclusive. The disengagen'ieut ot' the springs 41 and 43 from the springs 42 and 44 opens the circuit of the line relay 1t. The line relay 1o being slow acting does not fall back immediately. however, but holds the plunger arm in an operated position until a holding ground is supplied to the holding winding 14 from the selector E. The engagement of the springs 1S and 21 with the springs 22 and 2o, respectively, extends the suhscribers line to the line relay 26, of the selector l". )Vlien the connection is thus extended to the selector l l,the calling substation receives `current through the line relay 26 of the selector E. Thelne relay 26, upon energizing, closes the circuit of the slow acting relay 33 over a cireuit as follows: from ground G13 through the springs 112 and 113, through the relay 38 to battery. 'The relay 33, upon energizing, closes a circuit for the, holding winding 14 and the slow acting relay 17 of the line switch C. This circuit is from ground G through the springs 56, springs 23 and 19 and through the holdingr winding 14 to battery B, and also from the spring 19, through the springs 130 and the relay 17 t0 batter B. The Winding 14, upon energizing, hol s the armature 15 and the plunger arm 1l in their operated positions after the circuit of the pull-in winding is broken by the opening of the springs 47 and 48. The relay 17, upon energizing, closes a circuit from ground G15 through the springs 53 and 52 to the connector private, .bank contact which guards the substation A against being seized by a OnneCtOr. The

calling subsorilier now operates his calling device for the first digit 2, which momentarily separates the substation implnse springs 8 and 9 twice. Each timethescI springs arc separated the selector line relay 26 deiincrgizes. Since the relay 33 is slow to decncrgizc, `its armatm'e docs not have time to fallback during thc momentary in- ,terruptions of its circuit by the relay 26. l`l1erelore, cach time the relay 21' dciinergizcs. a circuit is closed through the relay 55 and the vertical magnet 27 as follows: from ground G through the springs l12and 111. springs 114 a'nd 114, relay vertical magnet 27 and the side switch wiper 34 (in first position) to battery B. The two impulses received by the vertical n|agnet 27 cause it to raise theA shaft wipers 29, 3() and 31 two steps to a position opposite the second leve] ot' bank contacts. The slow aoting'rtl` lay 55. which is included in the operating circuit of the vertical magnet 27',V closes av circuit through the private magnet 32 and keeps it closed until after the last Aiinpulse is delivered for the digit. rl`he. said circuit extends from ground G through thc springs 122 and the privatc magnet 3;) to battery li. Yhen the relay 55 docs deiinergize, it breaks the circuit ot' the privat(I magnet $52. which in turn denergizcs and permits the side switch to pass to second position. In second position the side switch lwiper 34 completes a circuit through the rotary magnet 2H. The side switch remains iu second position and causes thc rotary magnet to operate in a manner similar to that of a buzzer to4 rotate the shaft wipers stcp by step over the bank contacts o1 the second level until the wipers reach the contacts of an idle trunk line, whereupon the side switch passes to third position. Should the tirst trunk of the level be busy. its private contact would be grounded, forming a circuit from the grounded private bank contact tlirough the private wiper 2&0, side switch wiper 35 (in second position) and the private magnet 32 to battery l, thus holding the private magnet energized and keeping the side switch in second position. At the first idle trunk the oircuit through the private magnet will be broken and allow the sidc switch to pass to third position. The moment the side switch wiper 34 passes from second to thirdv position, besides breakingr the eireuit of the rotary magnet, it closes the circuit of the lineswitching relay 4U. This circuit extends from ground (i: through the. springs 56 and the side switch wiper 254 (in third position) to battery B. The relay 40. upon energizing, disconnects thc line relay 2o from the line and extends the line connection through the line wipers 29 and E51 to the repeater F. whereupon its line relay 37 becomes encrgized in the same lnauuer in which the relay 2G was energized when the connection was first extended to thc selector F.

Upon the line relay 37 energizing. a cir# cuit is closed from ground G through the contact ot' springs 57 and 57 and the slow relay 3S tolmttcry. 'lhe relay 39. upon energizing. prcsscsthc springs 5S and 5t) into contact. thereby setting up'a circuit througlrthc windingl 39 of the relay 2&5). which docs not yct energize this relay. 'lhc rclay 37. upon energizing. also presses together 'thc springs (it). thereby closing a bridge across thc outgoing truuk liuc` which closes a circuit for thc line relay 7.3 ol' thc connector l. said circuit. being traced from ground (l5 through the lowcr winding ot' thc line relay 75. through thc springs 7S and l lon. the back-bridgc relay TG to the trunk conductor ti. through thc springs (it) of the liuc rclav 37 in the repeater l through thc coil H1. through thc winding 2W" of thc relay through thc -thc upper winding oi' thc line relay 75 oi the-connector l and through the springsl H2 and 83 of the busy relay 84 to battery B. The current thus caused to {iow through the Winding 39" of the relay B9 is opposed at this time by current flowing through the winding 39 over the circuit extending from ground G" through the springs 58 and 59 o' the relay 38 and the winding 3,9 to battery B. As a result the relay' 39 does not operate. The current flowing through the trunli causes the relay 81 to pull up and place ground (il on the released trunk to supply a holding circuit for the linelswitching relay 4() ot' the selector E, the holding winding 14: and the relay 17 of the line switch C, the original holding circuit oi which is 'broken when the relay 33 denergizcs and allows the springs 56 to separatev The energization of the line relay 75 of the connector-causes the circuit of the slow acting relay 8G to be closed. The central ofiice apparatus is now in a condition for the transmission of the second scrics ot impulses, whereupon the dial is operated in the usual manner, opening the circuit of the line relay 37 in the repeater F' twice momentarily. The slow relay 38 maintains its armature in an operated position during the transmission of the impulses. Each time an impulse is sent-that is, each time the line relay 37 drops back while the slow acting relay 38 is retainingr its armature in an attracted position-a circuit is completed from ground G* through the springs 57' and 3T of the relay 37 and the springs 8T of the relay 38 and through the relay S8 to battery B. The result is that the first time the circuit is broken for the second digit, the relay 8F- closes a direct bridge across the trunk, and since the relay 88 is slow acting` the bridge is maintained closed at the con tacts 89 and 90 din-ing the subsequent impi'ilses. The relay 88, upon pulling up, also places a ground from ground Gr' upon the rclcasc trunk to take the place of ground (i7, which will be disconnected when the re lay S1 dclincrgizes` due to said relay being short-circuited by the pullingr up of the rolay S8. Each time the armature f theline relay 3T drops back in unison` with the breaking of the circuit at thc calling subscribeNs telephone, it opens this bridge, thus repeat ing the impulses to the connector l. The connector line relay, as hcreinbefore stated, upon energizing` closes the circuit of the rc- .lcase relay 8G, which in turn places ground from G upon the release trunk 91, which, in case a selector similar to the selector E was used between the repeater F and the connector I, would hold up the lineswitching reiay of said selector. The relay B6 of the coi nector being slow acting docs not decnergize during the momentary interruptions of its circuit by the line relay 75, and consequently each time the latter denergizes, an impulse is transmitted through the vertical magnet G7." This circuit extends from ground (im through the springs 93 and 92, through the springs 94 and 95, relay 96, vertical magnet G7 and the side switch wiper G9 (in rst position) to battery B. The vertical magnet (37 receives two impulses over this circuit and operates to raise the switch wipers G4, (i5 and (ifi to a position opposite the second level of bank contacts. The relay 9G, which was included in series with the vertical magnet, rcniains energized during the entire time that impulses are being transmitted through it and operates to close the circuit of the privato magnet 73. After the last impulse is delivered7 the relay 9G opens thel circuit of the private magnet Tizi, which, upon decncrgizing, permits the side switch to pass to second position. The movement of the side switch wiper G9 from iirst to second position transfers the battery connection from the vertical magnet (i7 to the rotary magnet ($8. \Vhen the series ot impulses have been transmitted and the rclay 88 of the repeater F falls back, it is so adjusted that its springs and 98 make contact with the springs 9T and 99, rcspectively, before the springs 10() and 101 break contact, in this way insuring that the relay S1 will be pulled up and have placed ground (i upon the release trunk S5 before the relay 8B cuts ground G ol" said trunk 85. The calling subscriber now operates his callingderice for the last digit 2, in response to which the connector line relay operates to transmit two impulses through the rotary magnet (5S, whereby the shaft wipers are rotated onto thcy contacts of the desired line. This circuit extends from ground (im through thc springs Si?) and 92, springs 9i and 95, relay 9h, springs 102i and 102, rotary magnet (38 and the side switch wiper (39 (in second position) to battery l5. rThe relay 9C operates in response to the impulses for this digit in the same manner as for the previous digit to cause. the private magnet 7|?, to advance the side switch t'o third position. i

'lhc called subscriber is equipped with an additional liuc. switch C', similar in all respects to the line switch C. By the engagement of the side switch wipers 70 and 71 with their third-position contact points, the line connection is completed with the called line. llpon the engagement of the wiper 72 with its third-position cont-act point, a circuit is completed through the eut-ofi` wind- 'ing of the line switch C', the said circuit extending from ground G through the side switch wiper 72, private wiper (35, bank contact 135 of thercalled line switch, springs 52 and 54 and through the cut-off winding 14 to battery B. The cut-of winding 14', upon energizing, operates to disconnect the line relay 16 from the called substation A. The connection of ground G with the oonnvvtor privutv hunk vontavt o'l'thv vullvil liuv prvrvnts thv vutlvil liuv from living .wi/Avit In' soinv othvr vounvvtor su'itvh. By thv vngugvinvnt ot' thv siltv L \\'itvh wipvr nl) with ltr; liiI'fl-position vontm't point. thv rirvuit otl thv ringvr rvlu)r Ti' in vlosrilK This virvuit vxtvnil` troni grouuil (il: through thv intvrruptvr ltl. rvlzrv TT. \priug 4 lut; unil thv shlv sufitvh uipvv Il to liuttvry li'. 'l'hv ringing rvlui ilisvonnvvnl thv vulling linv troni thv vutlvil linv :nul liriilgvs thv ringing vurrvnt gvnvmtor lt livrons thv vullvil linv lo ignul thv vultvil sutisvrilivr. 'l`hv ringing rvhrr vnvrgizvil only iutvriuittvntl)- through thv inviliuin ol" thv iutvrruptvr 10.3. l'pon thv rvlnponsv otl tllv vullvil Hullstrihvi his linv is pro.'i\lv|l with talking vnrrvnt through thv niuilings ot' thv huvlt-hriilgv rvh lu)v T11, u'hivh rvluy`r upon vnvrgiziug. vlosvs thv virvuit throngh thv riugvr vuto1f rvluy ttt?. rl`hv suiil vil-ruit. vxtvniln from grounil 1i through thv hniilv sn'itrh u'ipvr T2 (in thiril po itioni` hupring 1115 uml 109 unil thv rvlu)v 1U? to liuttvr)v B. Thv relay 10T7 upon vnvrgizing. interrupts thv, virvuit ol' thv ringing rvhi)r 7T :it thv springs 10u um] vlosw` u loi-hing vii-(ruit For itsvlt through thv spring` 133. inllvpvmlvnt ot' thv springs tu mul 1HE). 'l`hv vnvrgizution o,Il tho rvhrv Tt? :11m rv\'vrvs thv rlirvvtion ot thv (curi-Pnt flowing in thv trunk vouihuztors` 02 :intl uit. This` rv\'vrsul otl vurrvnt vnusvs thv Winding Still ot' thv rvlujv i111 in tlml rvpvutvr F to :isluint thv Winiliug 311". the volnhinvtl force of thv two living uuttivivnt to operate the relay i111. thv opvrzition ot the relay 39 reversing thv clirvvtion ot' vurrvnt tvil out hy the rvpimitvr l*` to thv vulling Huhntzttion A.

.\l'trr thv vonvvrszition i5 voniplvtvil thv vonnvvtiou i rvtvusvil hy thv hunging up ot' thv rvvvirvr :it thv vulling substation in thv t'olton ing inuuuvr: Win-n thv ret-"viver alt' thv utwtution A in rvstorvil to thv S\\'it fl1-hoolc, thv .nvp'irut ion ot' thv lswitvh-hook.springs tlvl|o \"f` thv vnvrgixlng virvuitA ot thv rvpoutvr lirv rvlu)Y 21T. 'lhv rvluy 217, upon ilvtnvrgiz ing. `opvnn` thv vii-ruit otA thv connor/ttor lino rvlrrx' TJ :nul rvhrv H1. til-lubl vuusiug tho lvvnvrgizution ot thv rvluy S1. whivh, whvn tulling tmvlc` rvinovvn grolunl (l7 from thv rvtvusv trunk 8.1 thus opening the holiling virruit t'or thv lint-switvhing Ivlny 4() ot thv `uvlvvtor 1C :unl tho holiling winiling 14 unil voil 1'.' ot' thv lino switvh (l. The linosn itt-hing rvhrxV Attl. upon tlvinvrgizing. vlonvs thv rvlvuh'v virvuit from ground G1" through thv yuprings l 2 unil 111, through the springs 111 :nul 115, thi-:nigh thv springs 126 :nul 12.1. through thv otlnoruuil springs llt unil 1li` :unt through thv rvlvnsv umgnot, 316 to tuitlvr)r l. "lhv vuvrgif-iutiun of thv` relaas-:o nmgnvt :it: vuusvs thv shaft wipers :intl sitio Sn iti-h n'ipvrs to return to noruml position` it,-` own vii-ruit living opvnefl when thv Shaft luis rvuvhvil noruml by means of the off uornnil Aupringn llo :nul 11T. The holding n'iniling 1t ot thv linv Snitch C, upon devnvrgizing. ,-illows thv plunger arm 111:10 return to noruiul position. Thv lineI relay' 75 Yol' thv vonnvvtor. upon llvt:nvrgizing` opcnis thv rirvuity ot' thv rvluy ht, which, upon (levnvrgix'ing. voinplvtvn u virvuit vxtivntting t'roiu grouuil li through the springs 5121 and ft2. npringl 51T finit 11H. otlnorinnl spring- 132 :unl 1211 unil through thv rvlvuno muguet Tt to huttvr)v li. Tho vnvrgizution of thv rvlvmv inaljguvt` Tl vuusvs the lino Wipers nucl thihlv riti-1| n'ipnrn4 to rvturn to normal, its own vii-ruit living opvnvd :it the off-nornizil `npring 121;) :unl 1211 when the shaft: rvnvhvS noriunl.

lt haring hvvn vxpluinvil how one Suhsvritavr vstulilinlivn :i vonnvtttion :intl rvleusvs thv suine. it` will now hv explained how u vonnvvtion in prvrvntvd from living nmtlv with :i tuuuv linv, how the vulling subsvrihvfs linv switvh in rvlvzisvil und how thv vulling suhsvrihvv rvvvirvh,` u busy signal through his own iniliriiluzil switrh. 1t' the culled nurnhvr in luis)`- thvrv will lie :i guarding p0- tvntiul. upon thv vonnvvtor privutv hunk vontuvt. inst :is vxplziinvil in connection with thv linv sn'itvh (1. 'lhv vonnvvtor pri 'nto ipvr tif. upon vnguging thi` gum-fling vontuvt. unil hvt'orv tho siilv switch wipers have pussvil to thiril positioln voinplvtvs un vnvrgizing virvuit through thv rvluy S1. This vii-ruit vxtvnils from ground :it thv private lmnk vontnot through thv private wiper (15,

siete inviti-h wipvr 1:2 (in second position), springs 11) unil 111%` rvluy S11, springn1 121 unil 120 unit thv prirutv nnignvt, 75l to hut.- tvrv l2'. Thv rvluy S11. upon energizing, opvnny thv virvuit ot' thv vonnvr'tor linv rvluy T5 ut` thv springs H2 :unl 9:1 of the rvhiy 84. This opvning ot' thv virvnit` oll thv linvl rvluy T5 olE thv ioniut'tor l vunnvs thv, lvluy 8l :It thv rvpvutvr li' to ilvnvrgizv, thv Suhl relay H1 living Htightliv slow uvting. ulthough notl :is nun-h so un thv rvluy Ht? oth the connector I. Thv ilvinvrgizzition ol the reluy 81 rvniorvnl groiunl from tho I'vlvnsoil trunk 8.3, :is prvvouxly vxpluinvil. Thv Winding 14 ot thv linv switvh upon ilvtnvrgizing.y :allows thv :uniuturv l." to fall lmvk :nul tho springs l1 urul 1l; to innltv Contact with tho spring1 4; :init A11. rvspvvtivvly, The plini-u gvr 11 is withilruwn vl'rozu thv lumi( of vontui-ts t1H-2),thusopvningthocilcuit, of thv, tinv rvluy 3T ot' thv rvpvzitvr. Thu springs '11 :lull lit nmlting vontzuft with thv springs At2 unit 11` rvupvvtivvly, closes r1` oirvuit through thvy linv rvlny lli of thv line Switvh 'l`hv linv rvlfxy lt7 upon energizing, vornplvtv4 n holeting virtfuit, for thvy relay 17. Thv` rvluy 1T tnt not ilviuvrgizn whcn tho grounil uns: rvniovvil from thv rvlvusv trunk on uvvount ot` it living slow noting. Tho suiil virvuit vxtvnils from ground (12 through tho springs and 4C, springs 47 und 129 :nut

the relay 17 to battery B. The relay 17 remains energized over the above circuit and retains the circuit of the pull-in winding 13 open at the springs 47 and 48. The line switch C is thuf; prevented from tripping and the cut-off armature l5 is'prevented from operating. The. energization of the relay 16 closes a path for busy signaling current to the calling subscriber`s line as follows: from the lnisy machine Q through the springs 127 and 12H, springs 13 and ll, conductor 2, through the substation A, conductor 3, spl-ings 4l and 42 to ground and from ground back to the busy niachine Q. The subscriber, upon receiving the busy signal, replaces his receiver upon the receiver hook. The replacing of the receiver upon the receiver hook allows the switch-hook springs to Separate, which action opens the circuit of the line relay 1li, thus allowing the line switch (l to return to normal.- The relay Hah upon energizing, forms a locking circuit tor itself from ground G1 through Jthe springs lill', through they springs 13S and lin. relay nl, through the springs 120 and 121 and thc relay 73 to main battery l. The opening;a

'of the circuit of the line relay T by the relay 84 causes the Slow relay Sti to lle-energize, whereupon the release magnet T4A is encrgized and the connector releases, as preriously explained. The removal ol"l ground l7 from the release trunl also causes the deenergization ot the switching relay 4u ot' the selector l. whereupon the release niagnet 3G becomes energized and the selector releases, as previously explained.

It will thus be .seen that we have devised a very eilicicnt means for giving a calling subscriber a busy signal when a called substation located in a distant exchange is in use, without unnecessarily retaining` thc switches and trunk lines in use. thus causing a great sariingy in the number ot switches and trunks required in a telephone exchange. It will also readily be seen that should a trunk line be open for any reason` any pcr son attemptingr to'call over that particular trunk will be released and zgiven the busy signal. l

While we have illustrated our invention in connection with one particular type ot automatic system, it will, of course, be un derstood that it is capable ot' use with many other forms ol' systems` and is equally as well adapted lior use in connection with semi-automatic systcinsH--Yilnu is` syslcios in which a niannal -linh circuit is employed in combination with automatic means l'or cstablishing a connection between thc subscribers lines.

lVliat wc claim as our invention isz-- 1. In a. telephone system, ,a series ol switches for establishing connection between a` calling and a called telephone line, a repeuter,y and means in said repeater for transinitting;r back to the switches on the calling side of said repeater a release which is initiated on the called side of said repeater.

2. In a telephone system, a repeater, a connector, and means for opening the line circuit. beyond said repeater when the connector Strikes a busy line.

3. In a telephone system, a connector, a pair of coinluctors extending to said connector, a bridge across said conductors, and means l'or opening said bridge at a point between said conductors when said connector lands on a busy line.

l. ln a telephone system, a connector, a pair of conductors extending to Said connector. a bridge across said conductors1 ine-ans for opening said bridge at u point between said conductors when Said connector lands on a busy line, and means controlled by the openiiner of said bridge for releasing said connector.

. in a telephone system, a connector, a

t'ront bridge in said connector, means for opening said bridge when said connector lands on a busy line` and means controlled by the opening` of said bridge for releasing saidconnector and any other switches inrolwd in extending' the connection to Said connector. li. ln a telephone system. a calling line,y a called line. a link for connecting the two, said link divided into lhree inductively connected sections. :in automatic progressively movable trunliinijr switch for connecting the calling;P line with the first section ot said linh. a relay connected with the :second sec tion ol' said lin li. release means for restoring Said sn'ilcli to normal to release Said connection. said rclcasc mains controlled by said relay. another relay associated with the third section ol' said linl". said rclay rontrolling' said lirst relay` a busy tcst circuit for thc called liuc. means for applyingir a busy potential thereto. lhe said second relay responsive to .said busy potential to control said lirst rclay to release said switch whine by thc connection is broken.

T. ln a tch-phone system. a calling' line, a callcd line. a link for connecting; the two, said iinl; divided into three inductively connected sections, :1n automatic progressively movable ranking .switch for connecting the callin; t linc with the lli-st section ol' said link` a relay across tbc second section of said linln rclcasc means for restoring' lsaid switch to normal lo release said connection, said release means` controlled by said relay. another relay associated with the third section of said linl.:` :said iclay controlliner said first relay` a busy test circuit for ihc called line, iin-ans l'or applyingr a busy potential thereto, the eaid second relay responsive to said busy potential to control said first relay to release said first switch whereby the connection is broken.

8. In a telephone system, a calling line` a called line. a link for connectingr the two, said link divided into tlii'ee inductively connected sections. an automatic progressively movable trunkine,r switch for connecting the calliiugr line with the lirst section ot' said link, a relay connected with the second section ot' said lilik. i'cleascineaus for restoring said switch to noi'nial to release said connection. said release lneans controlled by said relay. aiiotliei' relay associated with the thii'd section ot' said link. said i'elay controlling said first relay. a busy test circuit for the called line. means for applying' a busy potential thei'eto. the Vsaid second relay responsii'e to said busy potential to conlrol said ii'st relay to release said first switch whereby' the ciinnection is broken. a source ot' signaling' current. said source controlled by said release means when the connection is broken for applying' said signaling' ciii'reiit to the calling line to lefive the calling;l subscriber a signal.

i). 1n a telephone system, a calling' line. a called line, a link for connecting the two. said link divided into three india-tivelyl con nected sections, an automatic progressively movable trunking switch for connecting the calling line with the l'irst section of said link, a relay across the second section otl said link, release means for restorintr said switch to normal to release said connection. said re lease meanscontrolled by said relay, another relay associated with the third section ot said link,.said relay controlling said h'i'st relay. a' busy test cii'ciiit tor the called line, means for applyingr a busy potential thereto. the said second relay responsive to said busy potential to control said lirst relay to release said lirst switch wliei'eby the connection is broken. a source ot signaling current. said source'controlled by said release means when lthe connection is broken for applying said signalinglr current to the calling liuc to tive the'callingi,r subscribe' a signal.

lt). ln a telephone system. :i callin;r line and a called line. a link t'or cstablishing i a talking' circuit between the two lilies. talking conductors in each side ot' said link divided into three iiuluctively connected sections, an

automatic progressively movable ti'nnkingr switch for connectin,f Ir thc talking' conductors of the callingr line with the talking conductors of the irst section ot the link, a relay across the talking;r conductors ol the secondl section of said link. release means t'or restorimgr said switch to normal to release said connectioi said release meanscontrolled by said relay 'over a circuit excluding ,the talkingA minductors. another relay associated with the third section of the said link, said relay controlling said first relay ove a circuit including the talkinlglr conductors, automatic pros gressively n'iovable switching means for the link for finding' the called line, a busy test circuit t'or the called line, means for applying a busy potential thereto, said second relay responsive to said busy potential over a circuit excluding: the talking conductors to release said lirst switch whereby the conliectioii is broken.

1l. 1n a telephoneA system, a calling' line and a called line, a link for establishing a talking circuit between the two lines, talking conductors in each side ot' said link divided into three inductively connected sections, an automatic progressively movable trunkii'ig' switch for connecting' the talking' conductors ot' the calling' line withthe talking: eonduc tors of the 'ii'st section ot' the link1 a relay across the talking' conductors ot the second section ot' said link. release means for restoringr said switch to normal to release said connection. said release means controlled b v said relay over a circuit excluding! the talking).` conductors. another relay associated with the third section ot' the said link. said relay controlling' said til'st relay ovei' a circuit inclnd ing the two sides ot' the talking' conductors in series. automatic progressively movable switching means t'oi' the linkft'or finding' the called line. a busy test circuit for the called line. means for applying' a busy potential thereto. said second relay responsive to said busy potential over a circuit er\'cluding1r thetalkingi conductors lo release said first switch whereby the connection is broken.

1;). ln a telephone system. a calling: line and a called line. a link t'or establishingr a talking circuit between the two lilies. talking' com-luctors in cach side ot' said link divided into three iiiductivcly connected sections. an automatic progressively movable trunking switch t'oi' connecting' the talkinglr conductors oll the callin; r line willi the talking conduccircuit for the called iinc. means for applyi ing a liu-sy potential thereto. said second ref lay responsive to said busy potential over a circuit excluding,r the talking conductors to release said lii'st switch whereby the connection is broken. a source of signaling' current. said sourceI controlled by said release means when the connection is broken l'or applvinaf said signaling'current to the calling line to give the calling subscribe a signal.

13. ln a telephone system, a callin line and a called line, a link for establishing a talking circuit between the two lines, talking conductors in each side ot' said lilik divided into three inductively connected sections, an automatic progressively movable trunking switch for coi'inectiiig the talaking conductors of the calling liiie with the talking conductors of the first section ol'v the link, a relay across the talking conductors of the second section of said link, release means t'or restoring said switch to normal to release said connection, said release means controlled by said relay over a circuit excluding the talking conductors, another relay associated with the third sei-tion ot' the said link, said relay controllingr said first relay over a circuit including the two sides of the talkingl conductors in series, automatic progressively movable switching means for the link for finding the called line. a busy test circuit for the called 'line means for applying a busy potential thereto. said second relay responsire to said busy potential over-a circuit ex cluding the talking conductors to release said first switch whereby the connection is broken, a source of signaling current, said source controlled by said release means when the connection is broken for applying said signaling current to the calling line to give the calling subscriber' a signal.

14. In a telephone system, a calling line, a called line, a link for connectin the two, .said link divided into three inductively c0nnected sections, an automatic progressively movable trunking switch for connectingr the calling line with the first section of said link, a relay connected with the second section of said link, release means for restoring said switch to normal to release said connection, said release means controlled by said relay, another relay associated with the third section of said lilik, said relay controlling said first relay, a busy test circuit for thecalled line, means for applying a busy potential thereto, the said second relay responsive to saidv busy potential' to control said rst' relay to release said switch whereby the` connection is broken, a source of si"s 2nalin, ,f 1r current, a relay fcr the calling line for applying said signaling current to said line, the circuit of said third relay controlled by said switch to close the saine when the connection is released.

15. ln a telephone system, a calling line, a calli-d line, a link for connecting the two, said link divided into three inductively con nccteil sections, an automa-tic progressively \niovable titunking switch for connecting the calling line with the first section of said link, a relay across the second section of said link, release means for restoring said switch r 6o to normal to release said connection, said release means controlled by said relay, another relay associated with the third section ofv said link, said relay controlling said lirst re lay, a busy test circuit for the called line, means for applying a busy potential thereto, the said second relay responsive to said busy potential to control said first relay to release said switch whereby the connection i." broken, a source. ol. signaling current, a relay for the calling line for applying said signaling current to said line, the circuit ot' said third relay controlled by said switch to close the same when the connection is released.

16. In a telephone system, a calling line and a called line, a link for establishing a talking circuit between the. two lines, talking conductors in each side ot' said link divided into three inductively connected sections, an automatic l'nogressively movable ti'unking switch for connecting the talking conductors of the calling line ywith the talking conductors of' the first section of the link, a relay across the talking conduct/ors otl the second setion of said link, release means for restoring said switch to normal to release said connection, said release means controlled by said relay overa circuit excluding the, talking conductors, another relay associated with the third section of the said link, said relay controlling said first relay over a circuit including the talking conductors, automatic progressively movable switching means-:for the link for linding the called line, a busy test circuit for the called line, means for applying a busy potential thereto, said second relay responsive to said busy .potential over a circuit excluding the talking conductors to release said first switch whee- 4 by the connection is broken, a source of signaling current, a relay for the calling line for applying said signaling ciirrerit to said line, the circuit of said third relay controlled by said first switch to close the saine when the connection is released.

1'?. In a telephone system, a calling line and a called line, a link for establishi a talking circuit between the two lines, ta k ing conductors in each side of said link divided into three inductively conne ted sections, an automatic progressively `movable trunking switch for connecting the talking conductors of the calli-ng line with the talking conductors of the first section .of the link, a relay across the talking condiictors of the second section of said link, release means for restoring said switch to normal to release said connection, said release means oontrolled by said relay over a circuit excluding the talking conductors, another relay 'associated with the third section of the said link, said relay controlling said first relay over a circuit including the two sides o-f the talking conductors in series, automatic progressively movable switching means for the link for "making the called line busy,

finding the called line, a busy test circuit for the called line, means for applying a busy potential thereto, said second relay responsive to said busy potential over a circuit excluding the talking conductors to release said first switch whereby the connection is broken, a source of signaling current. a relay for the calling line for applying said signallng current to said line, the circuit of said third relay controlled by said first switch to close the same when the connection is released.

18. In a telephone system, a series of switches for establishing connection between a calling and a called telephone line, a repeater, means in said repeater for transmitting back to the switches on the calling side of said repeater a release which follows as a result of an impulse by the calling subscriber for advancing a switch on the called side of the repeater.

19. In a telephone system, a calling and a called telephone line, a repeater, an automatic progressively movable switch for extending a connection from said calling line to said repeater, means including a second progressively movable switch for extending the connectlon from said repeater to said called line, and-means for releasing said switches if the called line is busy when an attempt is made to connect therewith.

20. In a telephone system, a calling telephone line, a switch for said line. a repeater, means for extending a connection from said switch to said repeater, a called line, an automatic progressively movable switch controlled through the medium of said repeater for finding the called line and for completing connection therewith, and means for releasing said switches when an attempt is made to connect with a called line which is busy.

21. In a telephone system, a calling telephone line, a switch jor said line, a repeater, means for extending a connection from said switch to said repeater, a ycalled line, an automatic progressivchy movable switch controlled through the medium of said repeater for finding the called line and for completing connection therewith, means for releasing said switches when an attempt is made to connect with a called liuc which is busy, and means associated with said first switch for giving the calling telephone a busy signal. t

22. In a telephone system, a calling and a called telephone line, 11u-ans including a repeater and automatic progressively movable switrhing mechanisms ior extending a connection between said lines, means for and means in one of said mechanisms responsive to the busy condition of the called linev for releasing said repeater and switching mechanisms.

Y between 23. In a telephone system, a. calling and a` called substation, lines for connecting said stations with the exchange, a. switchl indi-" vidual to said calling substation, a. repeater progressively 7a and a pluralit of automatic movable switc es for extending a connec-4 `t1on to the line of the called substation,`

means for making the called line busy, and means in one of said progressively movable switches responsive to the called line for releasing said switches and said repeater, and means associated with the individual switch for giving the calling substation a bus signal. l

24. In a teleplione system, phone line, a switch for said line, a repeater, means for extending a connection from said switch to said repeater, a called "rue, an automatic progressively movable switch controlled through the medium of said repeater a5 for finding the called line and for completing connection therewith, means for releasing said progressively movable switch, means controlled by said progressively movable switch for releasing said progressively movable switch attempts to connect with a busy called line, and means controlled by the release of said repeater for releasing said first switch.

25. In a telephone system. phone line, a switch for said line, a repeater, means for extending a connection from said switch to said repeater, a called line, an alltomatic progressively movable switch controlled` through the medium of said repeater 100 forlind ing the called line and for completing connection therewith, means for releasing said progressively movable switch, means controlled by said progressively movable switch for releasing said Inogressivcly movable switch attempts to connect with a busy called line, means controlled by the release of said repeater for releasing said first switch, and means associated with callingfr telephone ai busy signal.

26. In a telephone system, a series of switches for establishing connection between a calling and a` called telephone line, a repeater, and a relay in said repeater for trans- 115 mitting back to the switches on the calling slide of said repeater a release which is initiated on the called side of said repeater.

27. In a telephone system, a connector, a

pair of conductors extending to said connec- 120 tor, a bridge across said conductors, and a busy test relay for opening said bridge at a point between said conductors when said connector lands on a busy line.

28. In a telephone system, pair of conductors extending to said connector, a bridge across said conductors, a busy test relay for opening said bridge at a point said conductors when said connector lands on a busy line,

thebusy condition of l a calling telesu said repeater when a calling telerepeater when said said lirst switch for giving the a connector, a

and means controlled by the opening of said bridge for releasing said connector.

29, In a telephone system, a connector, a front bridge in said connector', a busy test relay for opening said bridge when said connector lands on a. busy line, and means controlled by the opening of said bridge tor releasing said connector and any other switches involved in extending the connection to said connector.

30. In a telephone system, a series of switches for establishing connection between acalling and a called telephone line, a repeuter, a relay in said repeater -for transmitting back to the switches on the calling side of the repeater a release which follows as a result of an impulse by the calling subscriber for advancing a switch on the called side of the repeater.

31. Inca telephone system, a calling and a called telephone line, a repeater, an automatic progressively movable switch for 'extending a connection from said calling line to said repeater, means including a second progressively movable switch for extending the connection. from said repeater to said called line, and relay controlled means for releasing said switches if the called line is busy when an attempt is made to connect therewith.

3:2. In a telephone system, a calling telephone line, a switch for said line, a repeater, means for extending a connection from said switch to said repeater, a called line, an automatic progressively movable switch controlled through the medium of said repeater for nding the called line and for completing connection therewith, and relay controlled means for releasing said switches when an attempt is made to connect with a called line which is busy.

33. In a telephone system, a calling telephone line, a switch for said line, a repeater, means for extending a connection from said switch to said repeater, a called line, an automatic progressively movable switch controlled through the medium of said repeater `for finding the called line and for completing connection therewith, circuits for releasing said switches when an attempt is made to connect with a called line which is busy, and means associated with said first switch for giving the calling telephone a busy signal.

34. In a telephone system, a calling and a lallcd telephone line, means including a rcpeatcr and automatic progressively movable switching mechanism for extendin a Connection between said lines, means or making the called line busy, and a busy test relay in one of said mechanisms responsive to the busy condition of the called line for releasing said repeater and switching mechanisms..

35. In a telephone system, a calling and a called substation, lines for connecting said stations with the exchange, a switch individual to said calling substation, a repeater and a plurality of automatic progressively movable switches for extending a connection to the line of the called substation, means for making thc called line busy, and a relay in one of said progressively movable switches responsive to the busy condition of the called line for rele-.ling said switches and said repeater, and means associated with the individual switch for giving the calling substation a busy signal.

36. In a telephone system, means for connecting calling and called. lines comprising in serial relation a selector switch, a rcpeater, and a final connector, a control circuit for said connector including a relay in said repeater, means for opening said control. ci rcuit when the said connector'. at-

tempts to connect with a busy line, and a circuit controlled by said relay for releasing said selector.

Signed by us at Chicago, Illinois, this lflth day of November, 1913.

HARRY ll. HICSHEY. GEORGE A. YANOCIIOIWSKI.

lli'itncsses:

Maimonin li. MORGAN, Amen Oswann. 

